pkg/csource: add option to trace syscall results

This will be needed for testing of generated programs.

7 files changed, 64 insertions, 16 deletions

diff --git a/executor/common.h b/executor/common.h
index 9e6545926..1b9afd074 100644
--- a/executor/common.h
+++ b/executor/common.h
@@ -21,6 +21,10 @@
 #include <stdlib.h>
 #include <string.h>
 
+#if SYZ_TRACE
+#include <errno.h>
+#endif
+
 #if SYZ_EXECUTOR && !GOOS_linux
 #include <unistd.h>
 NORETURN void doexit(int status)
@@ -396,6 +400,9 @@ static void loop()
 	if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
 	}
 #endif
+#if SYZ_TRACE
+	printf("### start\n");
+#endif
 	int call, thread;
 #if SYZ_COLLIDE
 	int collide = 0;
@@ -470,7 +477,11 @@ static void loop()
 		fail("pipe failed");
 #endif
 	int iter;
+#if SYZ_REPEAT_TIMES
+	for (iter = 0; iter < [[REPEAT_TIMES]]; iter++) {
+#else
 	for (iter = 0;; iter++) {
+#endif
 #if SYZ_EXECUTOR || SYZ_USE_TMP_DIR
 		// Create a new private work dir for this test (removed at the end of the loop).
 		char cwdbuf[32];
diff --git a/pkg/csource/common.go b/pkg/csource/common.go
index ebc085c7a..a03fba056 100644
--- a/pkg/csource/common.go
+++ b/pkg/csource/common.go
@@ -95,6 +95,9 @@ func defineList(p, mmapProg *prog.Prog, opts Options) ([]string, error) {
 	if opts.Repeat {
 		defines = append(defines, "SYZ_REPEAT")
 	}
+	if opts.RepeatTimes > 1 {
+		defines = append(defines, "SYZ_REPEAT_TIMES")
+	}
 	if opts.Procs > 1 {
 		defines = append(defines, "SYZ_PROCS")
 	}
@@ -122,6 +125,9 @@ func defineList(p, mmapProg *prog.Prog, opts Options) ([]string, error) {
 	if opts.Repro {
 		defines = append(defines, "SYZ_REPRO")
 	}
+	if opts.Trace {
+		defines = append(defines, "SYZ_TRACE")
+	}
 	for _, c := range p.Calls {
 		defines = append(defines, "__NR_"+c.Meta.CallName)
 	}
diff --git a/pkg/csource/csource.go b/pkg/csource/csource.go
index 66958f22b..895856ea3 100644
--- a/pkg/csource/csource.go
+++ b/pkg/csource/csource.go
@@ -27,13 +27,13 @@ func Write(p *prog.Prog, opts Options) ([]byte, error) {
 		calls:     make(map[string]uint64),
 	}
 
-	calls, vars, err := ctx.generateProgCalls(ctx.p)
+	calls, vars, err := ctx.generateProgCalls(ctx.p, opts.Trace)
 	if err != nil {
 		return nil, err
 	}
 
 	mmapProg := p.Target.GenerateUberMmapProg()
-	mmapCalls, _, err := ctx.generateProgCalls(mmapProg)
+	mmapCalls, _, err := ctx.generateProgCalls(mmapProg, false)
 	if err != nil {
 		return nil, err
 	}
@@ -60,6 +60,7 @@ func Write(p *prog.Prog, opts Options) ([]byte, error) {
 	}
 	replacements := map[string]string{
 		"PROCS":           fmt.Sprint(opts.Procs),
+		"REPEAT_TIMES":    fmt.Sprint(opts.RepeatTimes),
 		"NUM_CALLS":       fmt.Sprint(len(p.Calls)),
 		"MMAP_DATA":       strings.Join(mmapCalls, ""),
 		"SYSCALL_DEFINES": ctx.generateSyscallDefines(),
@@ -94,17 +95,20 @@ func (ctx *context) generateSyscalls(calls []string, hasVars bool) string {
 	opts := ctx.opts
 	buf := new(bytes.Buffer)
 	if !opts.Threaded && !opts.Collide {
-		if hasVars {
+		if hasVars || opts.Trace {
 			fmt.Fprintf(buf, "\tlong res = 0;\n")
 		}
 		if opts.Repro {
 			fmt.Fprintf(buf, "\tif (write(1, \"executing program\\n\", sizeof(\"executing program\\n\") - 1)) {}\n")
 		}
+		if opts.Trace {
+			fmt.Fprintf(buf, "\tprintf(\"### start\\n\");\n")
+		}
 		for _, c := range calls {
 			fmt.Fprintf(buf, "%s", c)
 		}
 	} else {
-		if hasVars {
+		if hasVars || opts.Trace {
 			fmt.Fprintf(buf, "\tlong res;")
 		}
 		fmt.Fprintf(buf, "\tswitch (call) {\n")
@@ -145,7 +149,7 @@ func (ctx *context) generateSyscallDefines() string {
 	return buf.String()
 }
 
-func (ctx *context) generateProgCalls(p *prog.Prog) ([]string, []uint64, error) {
+func (ctx *context) generateProgCalls(p *prog.Prog, trace bool) ([]string, []uint64, error) {
 	exec := make([]byte, prog.ExecBufferSize)
 	progSize, err := p.SerializeForExec(exec)
 	if err != nil {
@@ -155,11 +159,11 @@ func (ctx *context) generateProgCalls(p *prog.Prog) ([]string, []uint64, error)
 	if err != nil {
 		return nil, nil, err
 	}
-	calls, vars := ctx.generateCalls(decoded)
+	calls, vars := ctx.generateCalls(decoded, trace)
 	return calls, vars, nil
 }
 
-func (ctx *context) generateCalls(p prog.ExecProg) ([]string, []uint64) {
+func (ctx *context) generateCalls(p prog.ExecProg, trace bool) ([]string, []uint64) {
 	var calls []string
 	csumSeq := 0
 	for ci, call := range p.Calls {
@@ -185,7 +189,7 @@ func (ctx *context) generateCalls(p prog.ExecProg) ([]string, []uint64) {
 		if emitCall {
 			native := ctx.sysTarget.SyscallNumbers && !strings.HasPrefix(callName, "syz_")
 			fmt.Fprintf(w, "\t")
-			if resCopyout || argCopyout {
+			if resCopyout || argCopyout || trace {
 				fmt.Fprintf(w, "res = ")
 			}
 			if native {
@@ -219,6 +223,9 @@ func (ctx *context) generateCalls(p prog.ExecProg) ([]string, []uint64) {
 				}
 			}
 			fmt.Fprintf(w, ");\n")
+			if trace {
+				fmt.Fprintf(w, "\tprintf(\"### call=%v errno=%%d\\n\", res == -1 ? errno : 0);\n", ci)
+			}
 		}
 
 		// Copyout.
diff --git a/pkg/csource/generated.go b/pkg/csource/generated.go
index 7cd6f8777..7be8ca329 100644
--- a/pkg/csource/generated.go
+++ b/pkg/csource/generated.go
@@ -15,6 +15,10 @@ var commonHeader = `
 #include <stdlib.h>
 #include <string.h>
 
+#if SYZ_TRACE
+#include <errno.h>
+#endif
+
 #if SYZ_EXECUTOR && !GOOS_linux
 #include <unistd.h>
 NORETURN void doexit(int status)
@@ -3613,6 +3617,9 @@ static void loop()
 	if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
 	}
 #endif
+#if SYZ_TRACE
+	printf("### start\n");
+#endif
 	int call, thread;
 #if SYZ_COLLIDE
 	int collide = 0;
@@ -3684,7 +3691,11 @@ static void loop()
 		fail("pipe failed");
 #endif
 	int iter;
+#if SYZ_REPEAT_TIMES
+	for (iter = 0; iter < [[REPEAT_TIMES]]; iter++) {
+#else
 	for (iter = 0;; iter++) {
+#endif
 #if SYZ_EXECUTOR || SYZ_USE_TMP_DIR
 		char cwdbuf[32];
 		sprintf(cwdbuf, "./%d", iter);
diff --git a/pkg/csource/options.go b/pkg/csource/options.go
index e60554120..a312c5db7 100644
--- a/pkg/csource/options.go
+++ b/pkg/csource/options.go
@@ -15,11 +15,12 @@ import (
 // Options control various aspects of source generation.
 // Dashboard also provides serialized Options along with syzkaller reproducers.
 type Options struct {
-	Threaded bool   `json:"threaded,omitempty"`
-	Collide  bool   `json:"collide,omitempty"`
-	Repeat   bool   `json:"repeat,omitempty"`
-	Procs    int    `json:"procs"`
-	Sandbox  string `json:"sandbox"`
+	Threaded    bool   `json:"threaded,omitempty"`
+	Collide     bool   `json:"collide,omitempty"`
+	Repeat      bool   `json:"repeat,omitempty"`
+	RepeatTimes int    `json:"repeat_times,omitempty"` // if non-0, repeat that many times
+	Procs       int    `json:"procs"`
+	Sandbox     string `json:"sandbox"`
 
 	Fault     bool `json:"fault,omitempty"` // inject fault into FaultCall/FaultNth
 	FaultCall int  `json:"fault_call,omitempty"`
@@ -34,8 +35,9 @@ type Options struct {
 	HandleSegv    bool `json:"segv,omitempty"`
 
 	// Generate code for use with repro package to prints log messages,
-	// which allows to distinguish between a hang and an absent crash.
+	// which allows to detect hangs.
 	Repro bool `json:"repro,omitempty"`
+	Trace bool `json:"trace,omitempty"`
 }
 
 // Check checks if the opts combination is valid or not.
@@ -101,6 +103,9 @@ func (opts Options) Check(OS string) error {
 	if opts.ResetNet && !opts.Repeat {
 		return errors.New("ResetNet without Repeat")
 	}
+	if !opts.Repeat && opts.RepeatTimes != 0 && opts.RepeatTimes != 1 {
+		return errors.New("RepeatTimes without Repeat")
+	}
 	return nil
 }
 
diff --git a/pkg/csource/options_test.go b/pkg/csource/options_test.go
index f43f2582e..ad86f8786 100644
--- a/pkg/csource/options_test.go
+++ b/pkg/csource/options_test.go
@@ -149,6 +149,11 @@ func enumerateField(OS string, opt Options, field int) []Options {
 			fld.SetInt(procs)
 			opts = append(opts, opt)
 		}
+	} else if fldName == "RepeatTimes" {
+		for _, times := range []int64{0, 10} {
+			fld.SetInt(times)
+			opts = append(opts, opt)
+		}
 	} else if fldName == "FaultCall" {
 		opts = append(opts, opt)
 	} else if fldName == "FaultNth" {
diff --git a/tools/syz-prog2c/prog2c.go b/tools/syz-prog2c/prog2c.go
index 9d89e8241..6abbd68b4 100644
--- a/tools/syz-prog2c/prog2c.go
+++ b/tools/syz-prog2c/prog2c.go
@@ -21,7 +21,7 @@ var (
 	flagBuild      = flag.Bool("build", false, "also build the generated program")
 	flagThreaded   = flag.Bool("threaded", false, "create threaded program")
 	flagCollide    = flag.Bool("collide", false, "create collide program")
-	flagRepeat     = flag.Bool("repeat", false, "repeat program infinitely or not")
+	flagRepeat     = flag.Int("repeat", 1, "repeat program that many times (<=0 - infinitely)")
 	flagProcs      = flag.Int("procs", 1, "number of parallel processes")
 	flagSandbox    = flag.String("sandbox", "", "sandbox to use (none, setuid, namespace)")
 	flagProg       = flag.String("prog", "", "file with program to convert (required)")
@@ -33,6 +33,7 @@ var (
 	flagNetdev     = flag.Bool("netdev", false, "setup various net devices")
 	flagResetNet   = flag.Bool("resetnet", false, "reset net namespace after each test")
 	flagHandleSegv = flag.Bool("segv", false, "catch and ignore SIGSEGV")
+	flagTrace      = flag.Bool("trace", false, "trace syscall results")
 )
 
 func main() {
@@ -59,7 +60,8 @@ func main() {
 	opts := csource.Options{
 		Threaded:      *flagThreaded,
 		Collide:       *flagCollide,
-		Repeat:        *flagRepeat,
+		Repeat:        *flagRepeat != 1,
+		RepeatTimes:   *flagRepeat,
 		Procs:         *flagProcs,
 		Sandbox:       *flagSandbox,
 		Fault:         *flagFaultCall >= 0,
@@ -72,6 +74,7 @@ func main() {
 		ResetNet:      *flagResetNet,
 		HandleSegv:    *flagHandleSegv,
 		Repro:         false,
+		Trace:         *flagTrace,
 	}
 	src, err := csource.Write(p, opts)
 	if err != nil {